The electromagnet/flap-armature system of such dot matrix pin print heads is of relatively complex construction which often provides insufficient operative guidance of the armature, requires costly and bulky configuration of the armature and is characterized by low magnetic fluxes with substantial stray flux.
It is known (as for example disclosed in European Patent No. 0 152 117) to develop a laminated armature as a flap armature and to provide it with a spring pivot. Such spring pivots, however, are expensive and problematic with regard to the material. Moreover, only with great difficulty can the spring pivot arrangement provide a favorable magnetic flux through the secondary air gap.
Where construction of the armature is effected without a spring pivot so as to produce an armature of solid material, it is known to facilitate guidance of the armature by way of a supporting pin and rubber ring which are both arranged on one side of the armature (as in European Patent No. 0 157 014), or to guide the armature with recesses between projections (as in European Patent No. 0 110 662); still another known guidance arrangement (as in U.S. Pat. No. 4,140,406) consists of a plug or slot mounting of the armature at the radially outer end in conjunction with radially inner lateral guidance.
All of these guidance constructions and procedures presuppose a complicated manufacturing method and are not very precise. The guidance of the magnetic flux in such constructions is furthermore unsatisfactory. In addition, higher drive forces and, correspondingly, larger electromagnet coils--i.e. with a higher number of ampere turns--are also required for such heavy armatures.